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Wyniki wyszukiwania dla: FAST IMPEDANCE MEASUREMENTS
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Poultry meat freshness evaluation using electronic nose technology and ultra-fast gas chromatography
PublikacjaTo ensure that chicken meat products are safe to consume, it is important to be able to reliably determine its shelf-life. To assess the applicability of ultra-fast gas chromatography and electronic nose technology in evaluation of poultry, an analysis of the headspace of ground chicken meat samples refrigerated over a period of 7 days was performed. Chemometric techniques were used to mine additional information from a multiparametric...
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Displacement measurements during load testing of railway arch bridge
PublikacjaThe paper discusses issues concerning load tests carried out on a twin-track, arch railway bridge over the Martwa Wisla river in Gdansk. Currently, it is the bridge with the longest span in its class in Poland. The load-bearing structure consists of three no-hinge arches and an orthotropic deck suspended from them. The studies of the structure assumed the performing of static and dynamic tests. The paper presents the method for...
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Analyzing the Geometry of the Turnouts and Their Adjustment Basing on the Tacheometer Measurements
PublikacjaThe article presents the results of tacheometric measurements of a station throat, as well as the method of data preparation and analysis. The calculations covered the verification of the geometry and the location of railway turnouts and crossings. The analyses were performed for the selected parameters of the turnout geometry, including their lengths and track gauge in main sections. In addition, the data were analyzed to confirm...
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Design of reverse curves adapted to the satellite measurements
PublikacjaThe paper presents a new method for designing railway route in the direction change area adapted to the Mobile Satellite Measurements technique. The method may be particularly useful in the situations when both tangents cannot be connected in an elementary way using a circular arc with transition curves. Thus, the only solution would be the application of two circular arcs of opposite curvature signs, that is, the use of an inverse...
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Multi-Taper-Based Automatic Correction of Non-Anechoic Antenna Measurements
PublikacjaPrototype measurements belong to the key steps in the development of antenna structures. Although accurate validation of their far-field performance can be realized in dedicated facilities, such as anechoic chambers, the high cost of their construction and maintenance might not be justified if the main goal of measurements is to support teaching or low-budget research. Instead, they can be performed in non-anechoic conditions and...
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A fast time-frequency multi-window analysis using a tuning directional kernel
PublikacjaIn this paper, a novel approach for time-frequency analysis and detection, based on the chirplet transform and dedicated to non-stationary as well as multi-component signals, is presented. Its main purpose is the estimation of spectral energy, instantaneous frequency (IF), spectral delay (SD), and chirp rate (CR) with a high time-frequency resolution (separation ability) achieved by adaptive fitting of the transform kernel. We...
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Fast Low-fidelity Wing Aerodynamics Model for Surrogate-Based Shape Optimization
PublikacjaVariable-fidelity optimization (VFO) can be efficient in terms of the computational cost when compared with traditional approaches, such as gradient-based methods with adjoint sensitivity information. In variable-fidelity methods, the directoptimization of the expensive high-fidelity model is replaced by iterative re-optimization of a physics-based surrogate model, which is constructed from a corrected low-fidelity model. The success...
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Impedance monitoring of fuel cell stacks
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Local impedance spectra of organic coatings
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Analyzer for spectroscopy of low-impedance objects
PublikacjaW artykule przedstawiono analizator umożliwiający pomiar impedancji w zakresie 1 ohma < |Zx| < 100 Mohma. Zastosowano w nim nowe rozwiązania dotyczące obwodu wejściowego i techniki detekcji fazoczułej sygnałów pomiarowych. Obwód wejściowy zaprojektowano w postaci 5-zaciskowej sondy pomiarowej, która umożliwia ograniczenie wpływu rezystancji, indukcyjności i pojemności pasożytniczych na błąd pomiaru impedancji w szerokim przedziale...
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Impedance spectroscopy of undoped cerium oxide.
PublikacjaW pracy przedstawiono badania impedancyjne niedomieszkowanego tlenku ceru. Wyniki wskazują na występowanie zjawiska dyfuzji,???? które nie są (.. jest.?)związane z odpowiedzią elektrodową. Rozważania teoretyczne dopuszczają obserwowanie impedancji Warburga, która reprezentuje zjawisko dyfuzji w przewodnikach mieszanych, jednakże niewiele informacji na ten temat można znaleźć w literaturze. W związku z tym szczegółowe badania zródła...
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Impedance spectroscopy of single chamber SOFC.
PublikacjaMechanizm działania jednokomorowego ogniwa paliwowego SOFC, które pracuje w mieszaninie powietrza i paliwa, nie jest do końca zbadany. W tej pracy przedstawiono wyniki badań ogniwa paliwowego zbudowanego z tlenku cyrkonu stabilizowanego itrem jako nośnego elektrolitu, cermetu z tlenku niklu jako anody i perovskitu LSCF jako katody w temperaturach 500-700C z użyciem mieszaniny propanu i powietrza. Wykorzystując spektroskopię impedancyjną...
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Local impedance spectra of organic coatings
PublikacjaPublikacja przedstawia nowe podejście do lokalnych spektroskopowych pomiarów impedancyjnych powłok organicznych, oparte o mikroskop sił atomowych pracujący w trybie kontaktowym. Pomiędzy nieporuszającą się igłę mikroskopu i podłoże metalowe pokryte powłoką epoksydową przyłożono serię sinusoidalnych napięciowych sygnałów pobudzenia w zadanym zakresie częstotliwości. W ten sposób zarejestrowano lokalne widma w trybie "frequency by...
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THE APPLICATION EFFECTS OF CONTINUOUS SATELLITE MEASUREMENTS OF RAILWAY LINES
PublikacjaThe paper presents results of satel lite surveying of the railway's rout es, which have been conducted just after starting in Poland (in 2008) the Active Geodesy Network ASG-EU POS. Afterwards it was possible to effectively utilize the GNSS survey ing results for the inventory of the (exploring) railways in service. Already at the beginning of 2009, the research team from Gdansk University of Technology and Naval Academy in Gdynia,...
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Fast Multi-Objective Antenna Optimization Using Sequential Patching and Variable-Fidelity EM Models
PublikacjaIn this work, a technique for fast multi-objective design optimization of antenna structures is presented. In our approach, the initial approximation of the Pareto set representing the best possible trade-offs between conflicting design objectives is obtained by means of sequential patching of the design space. The latter is a stencil-based search that aims at creating a path that connects the extreme Pareto-optimal designs (obtained...
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Integrated model for the fast assessment of flood volume: Modelling – management, uncertainty and sensitivity analysis
PublikacjaThe specific flood volume is an important criterion for assessing the performance of sewage networks. It has been shown that its value is greatly influenced by the layout of the sewers in the catchment area, which is usually expressed by a fractal dimension. Currently, only mechanistic models (such as SWMM) enable the determination of the impact of the layout of the sewers on flooding volume, but they require additional and robust...
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Measurements of acoustic crosstalk cancellation efficiency in mobile listening conditions
PublikacjaThe cancellation of acoustic crosstalk is employed to enhance the stereo image in mobile listening conditions. The implementation of the crosstalk cancellation algorithm in Matlab is introduced. The measurement signals and equipment are described. A practical setup employing a mobile computer and a head and torso simulator is employed. The results of the measurements provided conclusions regarding the employment of acoustic crosstalk...
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Analysis of the influence of ferromagnetic contaminations in plastics on the measurements of disturbances of magnetic field of the Earth
PublikacjaPlastics can be contaminated with small particles or filings with ferromagnetic properties. These contaminations cause significant disturbances in the magnetic field in the case of taking measurements of very low magnetic fields. The analysis of the influence of contaminated plastics on magnetic measurements is presented in this paper.
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Measurements of ASON/GMPLS connection control layer performance according to the ETSI methodology
PublikacjaMeasurements of performance have always been crucial for evaluation of telecommunication systems, especially for implementation of network control elements responsible for connection handling which regards to bandwidth reservation, modification and release. That problem also arises in Automatically Switched Optical Network/Generalized Multiprotocol Label Switching (ASON/GMLPS) architecture, which is considered as one of the components...
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The Verification of the Usefulness of Electronic Nose Based on Ultra-Fast Gas Chromatography and Four Different Chemometric Methods for Rapid Analysis of Spirit Beverages
PublikacjaSpirit beverages are a diverse group of foodstuffs. They are very often counterfeited which cause the appearance of low quality products or wrongly labelled products on the market. It is important to find a proper quality control and botanical origin method enabling the same time preliminary check of the composition of investigated samples, which was the main goal of this work. For this purpose, the usefulness of electronic nose...
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Simulation-Based Design of Microstrip Linear Antenna Arrays Using Fast Radiation Response Surrogates
PublikacjaFast yet accurate technique for simulation-based design of linear arrays of microstrip patch antennas is presented. Our technique includes: (i) optimization of the corrected array factor of the antenna array under design for a phase excitation taper resulting in reduced side lobes; (ii) simulation-driven optimization of the array element for element dimensions resulting in matching at and about operational frequency, and (iii)...
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Underwater Navigation Ssystem Based on Doppler Shift – Measurements and Error Estimations
PublikacjaA new acoustic navigation system was developed to determine the position and speed of moving underwater objects such as divers and underwater vehicles. The path of an object and its speed were determined by the Doppler shifts of acoustic signals emitted by a transmitter placed on the object and received by four hydrophones installed at the periphery of the monitored body of water. The position and speed measurements were affected...
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Noise measurements on low noise pavements - problems with inhomogeneity of wearing course
PublikacjaDuring the last several years, when performing numerous CPX noise measurements on low noise pavements,significant inhomogeneity of the wearing course was observed in numerous cases. Similar problems were almost not existing regarding to the dense pavements.In general three main reasons of inhomogeneity can be defined. The first one are imperfections in technology of production of a asphalt mix or/and errors made already during...
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System setup and software for cyclic, staircase and square wave voltammetry measurements
PublikacjaHardware dedicated for electrochemical measurement sometimes does not allow performing certain voltammetry experiments. Staircase and square wave voltammetry, techniques which have many advantages comparing with standard voltammetric techniques, are rarely implemented in software controlling electrochemical measuring equipment. These methods, however, can be relatively easy realized with some addition...
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Sensing the onset of epoxy coating degradation with combined Raman spectroscopy/atomic force microscopy/electrochemical impedance spectroscopy
PublikacjaThe paper presents the results of investigation on epoxy resin durability upon 12-week exposure to UV radiation. The aim was early determination of the onset of epoxy degradation and for this purpose an epoxy film on steel substrate systems were periodically inspected using Raman spectroscopy, atomic force microscopy and electrochemical impedance spectroscopy. The behaviour of examined polymer could be divided into three periods: immunity,...
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Reliability of acicular grindable thermocouples for transient temperature measurements at sliding contacts
PublikacjaAcicular grindable thermocouples represent an interesting and prospective technique of temperature measurements at sliding contacts. This study aimed at the investigation of their reliability and accuracy as applied to the friction materials of various classes in contact with steel. The tests were conducted on a pin-on-disc tribometer under stationary and transient regimes. The experimental results were validated by comparing the...
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Distortion of speech signals in the listening area: its mechanism and measurements
PublikacjaThe paper deals with a problem of the influence of the number and distribution of loudspeakers in speech reinforcement systems on the quality of publicly addressed voice messages, namely on speech intelligibility in the listening area. Linear superposition of time-shifted broadband waves of a same form and slightly different magnitudes that reach a listener from numerous coherent sources, is accompanied by interference effects...
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Tracking body movement for radio channel measurements in BAN with indoor positioning system
PublikacjaThis paper presents indoor positioning system based on inertial navigation with additional distance measurements using UWB modems and map matching to increase accuracy and eliminate position drift. Such system may be used to track position of human body during radio channel measurements for body area networks. Performance of proposed system and limitations caused by inertial navigation are briefly described.
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The comparison of vodka, whisky and moonshine by using the electronic nose based on the technology of ultra-fast gas chromatography
PublikacjaVodka andwhisky are produced fromgrain distillates. Formerly these alcohols were very often counterfeited, by the made in home conditions spirit drink called moonshine, which is obtained by distilling a mash from the alcoholic fermentation. This study presents research aimed at checking the usefulness of the electronic nose using ultra-fast gas chromatography for the differentiation of whisky, vodka and moonshine. 12 samples of...
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The comparison of vodka, whisky and moonshine by using the electronic nose based on the technology of ultra-fast gas chromatography
PublikacjaVodka andwhisky are produced fromgrain distillates. Formerly these alcohols were very often counterfeited, by the made in home conditions spirit drink called moonshine, which is obtained by distilling a mash from the alcoholic fermentation. This study presents research aimed at checking the usefulness of the electronic nose using ultra-fast gas chromatography for the differentiation of whisky, vodka and moonshine. 12 samples of...
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PUBLICZNE ŚRODKI TRANSPORTOWE A SAMOCHÓD ELEKTRYCZNY W OBSŁUDZE PODRÓŻY MIEJSKICH W METROPOLII TRÓJMIEJSKIEJ
PublikacjaMetropolia trójmiejska ma wyjątkowo negatywne uwarunkowania terenowe dla funkcjonowania i rozwoju sieci komunikacji publicWyznej. Dzielnice położone w tzw. dolnym tarasie są dobrze skomunikowane za pomocą linii SKM i tramwajowych. Jedynie te środki komunikacji szynowej, przy częstotliwości połączeń nie większej niż co 10 minut, są konkurencyjne dla indywidualnych dojazdów samochodami osobowymi. Natomiast autobusy i trolejbusy utykające...
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Three electrode configuration measurements of electrolyte-diffusion barrier-cathode interface
PublikacjaMeasurements of a system consisting of cathode/doped ceria diffusion barrier/doped zirconia electrolyte were made using two- and three-electrode configuration. Results obtained on a three-electrode measurement configuration were compared with and reflect the results obtained in two-electrode configuration. Three-electrode measurements allowed separating the impact of the symmetrical interface in the investigated system. They also...
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Instantaneous impedance monitoring of AA 7075 aluminum alloy corrosion in borate buffer with admixed chloride ions
PublikacjaThe study presents a research capabilities of Dynamic Electrochemical Impedance Spectroscopy (DEIS) as a tool used for instantaneous on-line monitoring of corrosion processes on the example of AA 7075 aluminum alloy. A borate buffer with admixed chloride ions in a quantity ranging from 0.05 to 25 mM was used to represent different types of corrosion attack. The surface of samples specimens was evaluated before and after the tests...
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Miscanthus × giganteus root anatomical traits measurements
Dane BadawczeThis data set presents the optical microscope measurements/ images of Miscanthus × giganteus (M×g) roots. The experiment was performed under work package 1: "Properties characterisation of two types of biochar", task D_RT: Phyto-analyses (stress response of plants on biochar amendments) in cooperation with Aarhus University. A short term pot experiment...
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Accuracy of marine gravimetric measurements in terms of geodetic coordinates of land reference benchmark
PublikacjaThe article presents how the values of (3D) coordinates of land reference points affect the results of gravimetric measurements made from the ship in sea areas. These measurements are the basis for 3D maritime inertial navigation, improving ships' operational safety. The campaign verifying the network absolute point coordinates used as a reference point for relative marine gravity measurements was described. The obtained values...
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Dead-Time Effect Compensation Based on Additional Phase Current Measurements
PublikacjaThis paper proposes a new method of dead-time effect compensation. The proposed solution is based on additional phase current measurements realized by analog-to-digital converters. These measurements are carried out at the time instants specified by a pulsewidth-modulation (PWM) strategy. This makes it possible to estimate inverter currents at the commutation instants and, finally, to estimate the voltage error caused by dead time. This...
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Accurate rolling resistance Rolling resistance measurements can be influenced by a number of factors
PublikacjaTire rolling resistance is one of the most difficult-to-measure parameters of the tire/ pavement interface, especially if road measurements are required. First of all, it is necessary to measure a fairly small force in the system that is heavily loaded by other forces and subjected to many adverse effects causing measurement errors. The second problem is related to the fact that tire rolling resistance depends on many factors,...
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EXHAUST TEMPERATURE MEASUREMENTS OF THE MARINE TURBOCHARGED DIESEL ENGINES IN OPERATION
PublikacjaThe article presents the selected metrology issues concerning the exhaust temperature of the turbocharged marine engines during operation. The special concern has been paid on existing disturbances as well as thermodynamical interpretation of the recorded measurement signal. A diagnostic informativeness of the standard exhaust temperature’s measurements has worked out while the engine runs in steady states has been also considered...
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Measurements of High-Speed Data Transmission Radio Link for Special Applications
PublikacjaIn the article measurements of high-speed data transmission radio link for special applications were presented. Build measurement stand, measurement scenario and obtained results were briefly described. All conducted research work took place in real maritime environment.
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Novel Family of Single-Phase Modified Impedance-Source Buck-Boost Multilevel Inverters With Reduced Switch Count
Publikacjahis paper describes novel single-phase solutions with increased inverter voltage levels derived by means of a nonstandard inverter configuration and impedance source networks. Operation principles based on special modulation techniques are presented. Detailed component design guidelines along with simulation and experimental verification are also provided. Possible application fields are discussed, as well as advantages and disadvantages....
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Efficient Gradient-Based Algorithm with Numerical Derivatives for Expedited Optimization of Multi-Parameter Miniaturized Impedance Matching Transformers
PublikacjaFull-wave electromagnetic (EM) simulation tools have become ubiquitous in the design of microwave components. In some cases, e.g., miniaturized microstrip components, EM analysis is mandatory due to considera¬ble cross-coupling effects that cannot be accounted for otherwise (e.g., by means of equivalent circuits). These effects are particularly pronounced in the structures in¬volving slow-wave compact cells and their numerical...
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A Low-Cost System for Far-Field Non-Anechoic Measurements of Antenna Performance Figures
PublikacjaPrototype measurements are the key step in the development of antenna structures. Typically, their far-field characteristics are validated in expensive, dedicated facilities such as open range sites, or anechoic chambers. Despite being necessary for obtaining high-precision data (e.g., for device qualification), the use of costly infrastructure might not be fully justified when the main goal of measurements includes demonstration...
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The Use of Unmanned Surface Vessels in Bathymetric Measurements of Waterbodies with Highly Dynamic Seafloor Relief
PublikacjaThe early 21st century is a time when unmanned surface vessels (USV) are used in various measurement applications. Modern autonomous and unmanned vessels are increasingly often used in bathymetric measurements whose aim is to measure the seafloor with the sufficient positioning accuracy. Therefore, the use of USVs in hydrography can be seen as the beginning of a new era in this regard. This paper presents bathymetric measurements...
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Fast Multi-Objective Optimization of Narrow-Band Antennas Using RSA Models and Design Space Reduction
PublikacjaComputationally efficient technique for multi-objective design optimization of narrow-band antennas is presented. In our approach, the corrected low-fidelity antenna model (obtained through coarse-discretization EM simulations) is enhanced using frequency scaling and response correction, sampled, and utilized to obtain a fast response surface approximation (RSA) antenna surrogate. The RSA model is constructed in the reduced design space....
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Algorithms of fast service restoration in survivable multilayer networks
PublikacjaGłównym celem rozprawy jest zaproponowanie nowych modeli/algorytmów doboru tras zapewniających przeżywalność usług w sieciach IP-MPLS/WDM poprzez zastosowanie wyznaczonych zawczasu ścieżek zabezpieczających. Zakres pracy obejmuje: dokonanie przeglądu mechanizmów transmisji informacji w warstwowych sieciach teleinformatycznych IP-MPLS/WDM; szczegółowy opis sposobów zapewniania przeżywalności usług; zaproponowanie nowych metod doboru...
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Waveform design for fast clutter cancellation in noise radars
PublikacjaCanceling clutter is an important, but computation-ally intensive part of signal processing in noise radars. It is shown that considerable improvements can be made to a simple least squares canceler if minor constraints are imposed onto noise waveform. The proposed scheme is potentially capable of canceling clutter in real-time, even for high sampling rates.
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Toward Fast Calculation of Communication Paths for Resilient Routing
PublikacjaUtilization of alternate communication paths is a common technique to provide protection of transmission against failures of network nodes/links. However, a noticeable delay is encountered when calculating the relevant sets of disjoint paths using the available algorithms (e.g., using Bhandari’s approach). This, in turn, may have a serious impact on the ability of a network to serve dynamic demands...
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Radio Channel Measurements in 868 MHz Off-Body Communications in a Ferry Environment
PublikacjaIn this paper, a characterization of the 868 MHz off-body radio channel in BANs is presented. Measurements were carried out in a ferry environment using a specific set-up. A method for path loss using radio distance measurements (RDMs) was developed. It allows to automate the measurements process and make it independent from the variable speed of a moving person. Based on the observed path loss as a function of distance, the obtained...
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On deterministic procedures for low-cost multi-objective design optimization of miniaturized impedance matching transformers
PublikacjaPurpose This paper aims to investigate deterministic strategies for low-cost multi-objective design optimization of compact microwave structures, specifically, impedance matching transformers. The considered methods involve surrogate modeling techniques and variable-fidelity electromagnetic (EM) simulations. In contrary to majority of conventional approaches, they do not rely on population-based metaheuristics, which permit lowering...
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Mobility measurements in oxide semiconductors
PublikacjaPraca zawiera wyniki badań właściwości elektrycznych, optycznych i strukturalnych cienkich warstw ito i sno2. badania wykazały, że cienkie warstwy tlenków metali wykazują rezystywność charakterystyczną dla półprzewodników. poziom transmisji światła w zakresie widzialnym pozwala zaliczyć badane warstwy do materiałów przezroczystych. badane cienkie warstwy wykonano metodą rozpylania magnetronowego.